In order for your SIP Endpoint to receive calls from Twilio, you will use the same TwiML or REST API calls you use today. The only difference is that you will now be specifying your Twilio Interconnect Connection, by including the tnx parameter in the URI with the value of the desired Twilio Interconnect connection, for example:

We strongly encourage you to Whitelist all of Twilio's following IP address ranges and ports on your firewall for SIP signalling and RTP media traffic. This is important if you have Numbers in different regions and for resilience purposes (e.g. if North America Virginia gateways are down, then North America Oregon gateways will be used).